Sam Bankman-Fried, the chief executive of FTX, at a conference in Nassau, Bahamas, in April. FTX said on Nov. 11 that it was filing for bankruptcy. (Erika P. Rodriguez | New York Times/The Minnesota Star Tribune)

Runs on financial institutions are among the most fascinating and chilling tales in economics.

The bankruptcy of Jay Cooke and Company in 1873 was disastrous for the economy. The 1930 failure of the fourth-largest bank in New York City — the Bank of United States — helped push the economy into a depression.

The liquidity crisis at Bailey Building & Loan in "It's a Wonderful Life" nearly devastated the town. (OK, that's from a fictional tale you might watch over the holidays.)

Financial failures throughout much of history often damaged the broader financial system and economy.

Reminiscent of a bank run, the crypto empire of Sam Bankman-Fried filed for bankruptcy after investors ran for the exits. The latest crypto business collapse follows on the heels of another crash in the spring. Financiers estimate that trillions have vanished. Yet there hasn't been a "Lehman Moment" with crypto failures, at least so far. The failure of Lehman Brothers in 2008 deeply harmed the global financial system.

Crypto isn't that important to the financial system or economy despite the constant hype about digital currencies. Crypto is still looking for a reason to exist besides another opportunity to gamble. The dream among libertarian digital evangelists that crypto would transform the economy has been repeatedly dashed.

Remember when crypto was supposed to offer a valuable hedge against inflation? Oops. The mantra that crypto was a safe investment during times of chaos has also come up short considering our perilous times, including Russia's invasion of Ukraine and an energy crisis.

"I don't see where crypto has produced much value to society, and it's a fairly costly industry (if only in energy consumption)," writes George Mason University economist Scott Sumner.

Crypto may eventually find a mainstream reason to exist. For now, the collapse reinforces the insight that financial promises too good to be true should be avoided.

As I wrote in a recent column, crypto companies offering double-digit yields to get owners to deposit their crypto with them was an alarm bell when market rates were close to zero. High yields screamed high risk.

Another lesson: Even though financial institutions are making it possible for employees to invest some retirement savings in crypto, you should turn down the option. Finally, don't believe the hype. Bubbles always go pop!

There's nothing wrong with taking a fling with some taxable entertainment money to try your luck and learn about a financial innovation. Just limit the money at risk to your entertainment budget. Caveat emptor!

Farrell is economics contributor to the Star Tribune, Minnesota Public Radio and American Public Media's "Marketplace."